docs: def delete(self, model_name):
      """Delete a model.
  
      Args:
        model_name: the name of the model. It can be a model full name
            ("projects/[project_id]/models/[model_name]") or just [model_name].
      """
      full_name = model_name
      if not model_name.startswith('projects/'):
        full_name = ('projects/%s/models/%s' % (self._project_id, model_name))
      response = self._api.projects().models().delete(name=full_name).execute()
      if 'name' not in response:
        raise Exception('Invalid response from service. "name" is not found.')
      _util.wait_for_long_running_operation(response['name'])